Mine chock, mine prop, or the like



July 14, 1936. A. wlLsoN MINE CHOCK, MINE PROP-OR THE LIKE Filed NOV. 7, 1954 Fmi.

Patented `Iuly 14, 1936 UNITED STATES PATENT oFFicE Application November 7, 1934, Serial No. 751,963 In Great Britain November 7, 1933 1 Claim.

This invention relates to improvements in mine chocks, mine props and the like contrived to permit simple and eiective release of the chock, prop or the like when required but to ensure maintenance of the chock, prop or the like in operative position until it is due to be released.

A device according to the invention comprises telescopically nested box-halves the inner one of which is formed with a circularly arranged f3 series of teeth having inclined end faces spaced by interdental gaps and the other of which houses a rotatable element provided with a circularly arranged series of. teeth having inclined end faces complemental to the first-mentioned L series of teeth, and a manually operable lever extending through said element and the outer box-half and displaceable to permit rotation of said element.

A mine chock or prop device constructed in accordance with the present invention is illustrated in the accompanying drawing in which Fig. 1 is an elevation, Fig. 2 a plan View, and Fig. 3 a vertical section on the line a-a of Fig. 2.

The device shown comprises telescopically related upper and lower box-like halves I, 2, re-

spectively. The upper box half I is constituted as a casting having a closed upper end and an open lower end. The lower box half 2, which is also constituted as a casting, projects upwardly within the upper box half I and has an open upper end and a closed lower end constituting a base 2.

Journalled within the box half I is a cylindrical element 3 presenting a circular group of depending teeth 4 having inclined end faces 4 engageable, in the extended condition of the chock as shown, with mating inclined end faces 5 presented by a second circular group of up- 40 standing teeth 5 unitary with the box half. 2.

The cylindrical element 3 is formed with a diametral slot 6 traversed by a lever 1 which also traverses slots 8, 8' formed in opposed side walls of the box half I. The distal end of the lever 1 is formed with a hook 9 engageable, in the extended condition of the chock, with a projection I0 on one corner of the box half I whereby to lock the element 3 against rotation.

The inclination of the cooperative end faces 5 4', 5 of the sets of the teeth is preferably such that the chock is self -releasing under load, release being initiated by displacing the lever 1 endwise to disengage the hook 9 from the projection I0, whereupon the cylindrical element 3 and the lever 1 are turned through approximately 45, so that the teeth 4 drop into the interdental gaps between the teeth 5 and the box half I is permitted to descend bodily until its lower edge I abuts on the base flange 2 of the box half 2. 15

The box halves I and 2 and the lever 1 are rendered captive by means of a chain I I connecting the proximal end of the lever 1 with the box 2.

The chock structure described may be tted to the top of a tubular or other prop, in which event the chock structure is preferably inverted and there is provided on the closed end of the box half I a depending boss adapted for attachment to the upper end of. the prop.

I claim:-

A mine chock or prop device comprising telescopically nested box-halves, the inner o-ne of said box-halves formed with a circularly arranged series of teeth having inclined end faces and spaced by interdental gaps, a rotatable element housed within the outer box-half and provided with a circularly arranged series of teeth having inclined end faces complemental to the end faces of said first-mentioned series of teeth, and a 3f manually operable lever extending through said element and said outer box-half, said lever and said outer box-half being formed with inter-engageable portions whereby in one position of said lever said lever is locked and said element is restrained against rotation relatively to said boxhalves, said lever being shiftable to unlocked position whereby to permit rotation of said element.

ARCHIBALD WILSON. 

